Solo.
Went to the end and cleared the spoil from last weekends “enlargement process” to one side and managed to to get forward half a body-length into a small, draughting chamber/possible passage ~2m wide, ~3m long and ~0.4m high in places. There is quite a bit of loose debris and spoil to be cleared, but a quick bit of work with a bar revealed the floor is partly made up of a thin veneer of degraded calcite over sediment ~200mm thickness. Further clearance will need to be carried out on the weekend when a better evaluation of where this passage is going should be possible. Back to the main task of the evening which is the removal of the bulge in the floor of Toil and Trouble to ease progress, I must say it was very awkward working and am glad that it was dry.